1. Field of the Invention
The present disclosure generally relates to a maintaining device, a maintenance method, a computer program product, and a computer readable medium of a resistive random access memory and, more particularly, to a maintaining device, a maintenance method, a computer program product, and a computer readable medium for maintaining the normal operation of a resistive random access memory.
2. Description of the Related Art
Resistive random access memories (RRAMs) have an extremely low operating voltage, an extremely high read/write speed, and high miniaturization of the element size, and are in M/I/M or M/I/M/I/M (complementary) structure. Thus, resistive random access memories may replace the conventional flash memories and dynamic random access memories (DRAMs) as the main stream of memory elements of the next generation.
FIG. 1 shows a conventional resistive random access memory 9, which includes two electrodes 91 and a resistance changing layer 92 sandwiched between the two electrodes 91. The resistance changing layer 92 may be formed from a single or multiple materials. One electrode 91 may be grounded while the other one may be electrically connected to a voltage source V to receive different voltages (as shown in FIG. 2). Under the voltage supply of the voltage source V, the resistive random access memory 9 may perform at least one operational step, such as a setting step P1 and a resetting step P2. Accordingly, the resistive random access memory 9 may have a redox reaction and therefore can switch between the low resistance state (LRS) and the high resistance state (HRS). The two resistance states can be used to store two logic states of the data (such as 0 and 1).
Referring to FIG. 3, as the conventional resistive random access memory operates more and more frequently, the oxygen ions of the resistance changing layer 92 will gradually disperse. As a disadvantage, the resistance values of the LRS and HRS will become more and more close. Specifically, after the resistive random access memory operates for a large number of times (such as 1×108 times), the resistive random access memory can no longer function normally due to the small difference between the resistances of the LRS and HRS. Thus, the conventional resistive random access memory does not have a long service life and high reliability, leading to a higher cost of data storage.
In light of this, it is necessary to improve the conventional resistive random access memory.